Rather than bemoan wysiwyg shortcomings, let's look at what it is we're trying to do.
When building a page, or a site for that matter, the goal is to get the content onto the page in a well structured document: The choice of words, and the logical structuring of the text. Depending on the content, structuring includes the division of the text into paragraphs or sections, using lists or block quotes and so on. Then naming the structural elements for what they are; adding the html element tags.
If you're using a wysiwyg editor, you're forced to conflate composition and presentation (equivalent to typesetting). When composing the document, our attention should not be distracted by typesetting at the same time.
There is a side benefit to keeping the layers separate; a well structured html page will be fully functional and make complete sense to the visitor without any presentation or behavior elements. If not, the page is a failure.